Flexor Tendon Repair in Zone II With 6-Strand Techniques and Early Active Mobilization

Flexor Tendon Repair in Zone II With 6-Strand Techniques and Early Active Mobilization

Flexor Tendon Repair in Zone II With 6-Strand Techniques and Early Active Mobilization Denju Osada, MD, Satoshi Fujita, MD, Kazuya Tamai, MD, Tetsuhik...

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Flexor Tendon Repair in Zone II With 6-Strand Techniques and Early Active Mobilization Denju Osada, MD, Satoshi Fujita, MD, Kazuya Tamai, MD, Tetsuhiko Yamaguchi, MD, Akira Iwamoto, MD, Koichi Saotome, MD From the Department of Orthopaedics, Dokkyo University School of Medicine, Tochigi, Japan.

Purpose: There are many biomechanic studies of 6-strand suture techniques for active mobilization, but few reports have described the clinical outcome in zone II flexor tendon lacerations. We discuss the clinical results of zone II flexor tendon repair using 2 of these techniques followed by controlled early active mobilization. Methods: Six-strand sutures using the number 1 technique by Yoshizu or a triple-looped suture technique were used to repair flexor tendons in 27 fingers from 21 consecutive patients. Fingers were mobilized by combining active extension and passive or active flexion in a protective splint for the first 3 weeks after surgery. The follow-up period averaged 13 months. Results: Based on the original Strickland criteria, the results were excellent in 17 fingers, good in 9, and fair in 1. The average flexion was 62° for distal interphalangeal joints and 91° for proximal interphalangeal joints. None of the repaired tendons ruptured. Conclusions: The 6-strand flexor tendon suture technique followed by controlled active mobilization protected with a dorsal splint is safe, produces no ruptures, and achieves very good results in zone II flexor tendon laceration repair. (J Hand Surg 2006;31A:987–992. Copyright © 2006 by the American Society for Surgery of the Hand.) Type of study/level of evidence: Therapeutic, Level II. Key words: Active mobilization, flexor tendon, repair, zone II, 6-strand.

mproving results in zone II flexor tendon injuries remains a challenge to hand surgeons. Whether injured flexor tendons recover satisfactory function depends on meticulous surgical repair and postoperative care. Experimental studies1– 6 have shown that active mobilization of the digits with flexor tendon repair is effective in enhancing the healing process of the repair and in diminishing adhesion formation. Immediate controlled mobilization (passive flexion/active extension) introduced by Kleinert et al7 in 1967 has been well accepted and has been modified in several ways. In 1989, Cullen et al8 and Small et al9 reported the use of controlled active mobilization (active flexion/extension) but used a conventional Kessler repair. Ruptures in such active mobilization after conventional 2-strand repair occurred in 4% to 43% of patients.8 –13 Biomechanic studies on flexor tendon repair14 showed that the break strength is 24 N in conventional Kessler repair, 38 N in

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4-strand repair (Lee double-loop), and 53 N in the Savage 4-strand repair. In the Savage 6-strand repair, the average ultimate strength before breakage is 84 N.15 Repair strength increases with the number of core sutures.15 Despite the many biomechanic studies on 6-strand sutures for active mobilization,6,14 –21 few English-language reports have discussed clinical outcomes in zone II repairs.22–25 The articles by Savage and Risitano22 and Tang et al23 discussed techniques and included full clinical outcomes, but the Lim and Tsai24 and Sandow and McMahon25 detailed surgical but not clinical outcomes, except briefly, in technical review articles. In 1996, Yoshizu26 introduced 2 6-strand suture techniques (Yoshizu no. 1 [Y1] and triple looped [TL]) for early active mobilization. Since 1997, we have conducted flexor tendon repair with the 6-strand techniques described by Yoshizu26 followed by conThe Journal of Hand Surgery

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trolled early active mobilization.27 We detail the results of this combination for zone II flexor tendon injuries and compare them with those of previous studies using high-strength multistrand repair and early active mobilization.

Materials and Methods Patients Fingers with complete flexor digitorum profundus (FDP) lacerations in zone II with or without concomitant flexor digitorum superficialis (FDS) laceration were included in this study. Fingers with associated injuries other than digital artery and nerve injuries such as fractures, articular injuries, and skin defects were excluded. The total series of patients selected on the basis of these criteria consisted of 22 consecutive patients with 28 injured fingers who were treated at our institution between 1997 and 2003. One patient was lost to follow-up evaluation, so 21 patients with 27 fingers had a minimum of 6 months of follow-up evaluation. The patients consisted of 15 men and 6 women with an average age of 37 years (range, 13– 66 y). The injury-related data are outlined in Table 1. Surgical Technique The wound was extended using a Bruner incision, and a sheath flap was raised to expose the tendon, preserving the functionally important A2 and A4 pulleys. The FDP was repaired with 6-strand sutures, Y1 (Fig. 1A), or TL (Fig. 1B), as described elsewhere.26 The Y1 combines the Tsuge suture with a

Table 1. Details of Injuries in 27 Fingers No. of Fingers Dominant hand injured Cause of injury Sharp cut Blunt/crush Isolated complete FDP injuries Complete FDP and complete FDS injuries Finger injuries Index Middle Ring Small Fingers in patients with tendon repairs in ⬎1 finger of the same hand Primary repair (⬍24 h after injury) Associated injuries Digital nerve division Digital artery division

12 24 3 7 20 3 6 7 11 10 18 7 4

Figure 1. Six-strand suture techniques. (A) The Y1 technique: combination of the Tsuge suture with a 4-0 looped thread and the modified Kessler suture using a 4-0 double strand with 2 needles. (B) The TL technique using 3 Tsuge sutures with 4-0 looped thread.

looped thread and the modified Kessler suture using a double strand with 2 needles (Bear Medic Corp., Ichikawa, Japan), which was a newly designed suture material.26 The Tsuge suture was placed in the center of the FDP and passed farther through the tendon to avoid placing 3 knots at the same level on the tendon surface. We used 4-0 monofilament nylon for core sutures. The TL uses 3 Tsuge sutures with a 4-0 looped thread. Looped threads were inserted on the dorsoradial, dorsoulnar, and volar aspects of the tendon to minimize insult to the tendon blood supply, most of which comes from the tendon’s middorsal aspect.15,23,24 The suture in the volar center of the FDP was passed farther through the tendon to avoid placing 3 knots at the same level on the tendon surface.26 The TL is similar to the multiple looped suture described by Tang et al,23 which uses 3 threads of 4-0 looped nylon. A simple running peripheral epitenon suture was added with 6-0 monofilament nylon. Because the double strand with 2 needles (Bear Medic) was not available until 1999, the TL was used from 1997 to 1999 and the Y1 was used from 2000 to 2003. Nineteen FDP tendons had Y1 repairs and 8 had TL repairs. The FDS was repaired to its decussation (bifurcation) with 4-0 or 5-0 monofilament nylon horizontal mattress sutures or Tsuge sutures, but in the proximal part of zone II it was repaired with Y1 or TL and peripheral sutures. Five FDS tendons had a Y1 repair, 11 had a Tsuge repair, 2 had a horizontal mattress repair, and 2 were not repaired. The tendon sheath opening was excised where sutured areas of tendons caught on the edges of their sheath windows and obstructed free movement. The A2 and A4 pulleys were not excised

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completely, however, to prevent tendon bowstringing. All associated nerve divisions were repaired with 8-0 nylon, and all artery lacerations were not repaired. Postoperative Treatment A dorsal plaster splint was placed to hold the wrist in neutral, the metacarpophalangeal (MCP) joints at 30° to 40° of flexion, and the interphalangeal (IP) joints fully extended.26,27 The 3-0 monofilament nylon attached to all 4 fingertips was knotted proximally to 2 rubber bands and attached to the proximal forearm, running under a pulley placed in the palm. Mobilization was begun on the first or second postoperative day. Patients conducted 6 active IP joint extension exercises hourly, unloading the tension of the rubber bands by drawing them distally with the contralateral hand. Passive flexion produced by the rubber bands was increased by patients pushing the fingertips down with the contralateral hand. Patients also were instructed to hold the fingers gently and actively (isometric active flexion) for 2 to 3 seconds during passive flexion 5 to 6 times a day under the supervision of the surgeon or therapist. At night, the rubber bands were released from their attachment on the forearm and the fingers were splinted in an extended position. One or 2 days after the start of rehabilitation unassisted active flexion was allowed 5 to 6 times a day under the supervision of the surgeon or therapist. Contractures were watched for carefully, particularly in the proximal interphalangeal (PIP) joints. If evidence of contracture developed in the PIP joints, a pad was placed on the dorsum of the proximal phalanx or the dorsal splint was bent dorsally at the PIP joint to act as a fulcrum for extension. Patients remained hospitalized 4 weeks after surgery for active mobilization exercises under the supervision of the surgeon or therapist. At 4 weeks after surgery, the splint was removed and free active finger flexion and extension exercises were begun, with the night splint used for an additional 2 weeks. At 6 weeks after surgery, gentle resisted flexion was allowed. At 8 weeks after surgery progressive resistive exercise was started, and at 3 months after surgery power gripping was allowed. The functions of treated fingers were calculated using original Strickland and Glogovac28 criteria: (active PIP ⫹ distal interphalangeal [DIP] flexion ⫺ extension lag at PIP and DIP)/175° ⫻ 100 equals the percentage of normal active PIP and DIP motion. Results were classified as excellent (85%–100% of

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normal IP motion), good (70%– 84% of normal), fair (50%– 69% of normal), or poor (⬍50% of normal). Results were analyzed statistically using the chisquare test for unpaired groups, with a p value of less than .05 indicating a significant difference.

Results The average follow-up period for the 21 patients was 13 months (range, 6 –51 mo). Functions of the treated fingers were evaluated by the original Strickland and Glogovac28 criteria. Seventeen fingers were rated as excellent, 9 as good, and 1 as fair. In the 19 fingers with Y1 repair of the FDP tendon, 11 were rated as excellent, 7 as good, and 1 as fair. In the 8 fingers with TL repair of the FDP tendon, 6 were rated as excellent and 2 as good. No significant difference was seen between the 2 groups with different core sutures. In the 7 fingers that had isolated FDP tendon injuries, 6 were rated as excellent and 1 as good. In the 18 fingers with FDS tendon repair, 9 were rated as excellent, 8 as good, and 1 as fair. This difference between the FDP and FDS tendons was not statistically significant. Two fingers in which FDS repair was neglected were rated as excellent. In the 7 fingers accompanied by nerve injury, 4 were rated as excellent and 3 as good. In the 4 fingers accompanied by artery injury, 2 were rated as excellent, 1 as good, and 1 as fair. The average flexion was 62° for the DIP joint and 91° for the PIP joint. Loss of DIP extension (average, 9°) occurred in 3 fingers and loss of PIP extension (average, 13°) occurred in 11. Loss of IP extension exceeding 15° occurred in 5 fingers. In small-finger injuries 4 had a loss of IP extension exceeding 15°. None of the repaired tendons ruptured.

Discussion The repair must have sufficient strength to allow early active mobilization safely after flexor tendon tenorrhaphy and avoid tendon rupture. The repair strength increases with the number of core sutures.15 The double-strand technique with 2 needles was developed because each pass of the suture adds 2 strands to the core.26 Both Y1 and TL repairs involved 6-strand sutures and are easy to perform because they consist of commonly used Kessler and/or Tsuge techniques. Yoshizu et al29 evaluated the maximum tensile strength of Y1 and TL techniques using fresh human flexor tendons and found that the average loads producing a 3-mm gap were 42 N for Y1 and 37 N for TL. Kusano et al30 evaluated the mechanical strength of Y1 and TL during healing in a

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rabbit model and found that the maximum load for each suture producing a 3-mm gap did not differ significantly between the load measured at repair and the load measured at 1 week for either technique. The load 3 weeks after repair markedly exceeded the load measured at repair and at 1 week for either technique. The Y1 and TL repairs thus provide sufficient strength for early active mobilization exercises in the clinical setting. No significant difference was seen in clinical results between Y1 and TL repairs in our study. The presence of a nerve injury did not affect the results. It was not clear whether neurovascular or vascular repair influenced the results, however, because all associated nerve divisions were repaired and all artery divisions were not. Few reports have detailed the clinical outcome of zone II flexor tendon repairs using 6-strand sutures and early active mobilization.22–25 The original Strickland and Glogovac28 criteria are strict compared with other methods31–34 of assessing flexor tendon function because they exclude MCP joint motion. Many investigators8,12,13,35–37 thus regard this as most suitable for scientific and clinical purposes, particularly for zone II repairs. We compared the results of our series with previous studies25,38 – 41 that used high-strength multistrand repair followed by controlled active mobilization and evaluated them using the original Strickland and Glogovac28 criteria (Table 2). Savage and Risitano22 showed 45% excellent, 20% good, 20% fair, and 10% poor results for 20 fingers using the criteria of Buck-Gramcko et al.31 In contrast, our series showed 96% excellent and 4% good results using the same criteria. Tang et al23 showed 13% excellent, 57% good, 22% fair, and 9% poor results for 23 fingers using the American Society for Surgery of the Hand criteria.33 Similarly, our series showed 30% excellent, 67% good, and 4% fair results. Lim and Tsai24 showed 41%

excellent, 41% good, and 16% fair results for 32 fingers using the revised Strickland34 criteria. Similarly, our series showed 93% excellent and 7% good results. Both our study and that of Silfverskiöld and May38 showed superior results compared with other series. Silfverskiöld and May38 had 2 tendon ruptures but our series had none. The postoperative treatment in our series resembled that of Silfverskiöld and May.38 Results after zone II flexor tendon repair are related strongly to the amount of tendon excursion produced during early mobilization.42 It is easier to mobilize fingers actively with the wrist in the neutral position. The flexion angle of the MCP joint in our series was smaller than that in previous reports.25,38 – 41 These positions of postoperative splinting are achieved because Y1 and TL sutures are strong enough to allow a greater range of finger motion and tendon excursion.26,27,29 It is difficult to obtain a large IP joint range with active flexion alone because pain, swelling, and stiffness in the early postoperative period tend to inhibit voluntary active flexion or promote co-contraction of the extensor muscles.38 In our series, we therefore initially combined active flexion with simultaneous passive flexion. Our use of 4 finger rubber bands and pulleys provided continuous bending that increased passive flexion efficiently and overcame any initial stiffness. Rubber band traction is likely to develop flexion contractures in PIP joints, so for these contractures we placed a pad at the dorsum of the proximal phalanx or bent the dorsal splint dorsally at the PIP joint to act as a fulcrum for extension. As a result, a loss of IP extension exceeding 15° developed in only 5 fingers. Silfverskiöld and May38 shortened the dorsal splint to end at the PIP joint for flexion contracture of PIP joints, but we chose the dorsal splint that covers the fingertip to enable patients to remain in the same splint for rest and exercise.

Table 2. Comparison of Results With Other High-Strength Multistrand Repair and Controlled Active Motion in Zone II Using Original Strickland and Glogovac28 Criteria Study

No. of Fingers

Follow-up Period, mo

Good and Excellent Results

Rupture Rate (Fingers)

Lee,42 1990* Silfverskiöld and May,38 1994† Sandow and McMahon,25 1996‡ Kitsis et al,39 1998† Klein,40 2003* Osada et al (this study)‡

11 55 23 87 19 27

? 6 3-? 12 3 13

91% 96% 78% 89%§ 95% 96%

9% (1/11) 4% (2/55) 0 6% (5/87) 5% (1/19) 0

*Four-strand repair. †Two-strand plus cross-stitch or Halsted repair. ‡Six-strand repair. §Results included re-repaired case.

Osada et al / Flexor Tendon Repair in Zone II

Comparing the rupture rate in a 6-strand suture group, Savage and Risitano22 reported a 5% rupture rate in 20 fingers, Tang et al23 reported a 4% rupture rate in 51, Lim and Tsai24 reported a 3% rupture rate in 32, and Sandow and McMahon25 and our series report a 0% rupture rate. The postoperative rupture rate thus was lower in studies using 6-strand sutures followed by controlled active mobilization than in those using controlled active mobilization after conventional 2-strand repair.11,13,43 We believe that supervision of active mobilization exercises is as important as surgical technique or the postoperative rehabilitation regimen for achieving the clinical results. Hospitalization for postoperative rehabilitation of the flexor tendon repair is common in Japan because national medical insurance is required for all citizens and hospitalization is permitted as needed. Patients in our series thus were hospitalized for 4 weeks after surgery for active mobilization exercises supervised by the surgeon or therapist, thus ideally preventing ruptures in repaired tendons. Received for publication June 21, 2005; accepted in revised form March 2, 2006. No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article. Corresponding author: Denju Osada, MD, Department of Orthopaedics, Dokkyo University School of Medicine, 880 Kitakobayashi, Mibu, Shimotsuga-gun, Tochigi, 321-0293 Japan; e-mail: [email protected]. Copyright © 2006 by the American Society for Surgery of the Hand 0363-5023/06/31A06-0019$32.00/0 doi:10.1016/j.jhsa.2006.03.012

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